Ingestion, transmission, and persistence of Chino del tomate virus (CdTV), a new world begomovirus, by old and new world biotypes of the whitefly vector Bemisia tabaci

Two whitefly biotypes of Bemisia tabaci, from either the Eastern or Western Hemisphere, respectively, were compared with respect to their competency to ingest and their efficiency to transmit the New World begomovirus, Chino del tomate virus (CdTV). The AZ A biotype of B. tabaci originates from the arid southwestern USA and northwestern Mexico, while the B biotype has an origin in the Middle East or Northern Africa. The ability of these two vector biotypes to ingest and subsequently to transmit CdTV were evaluated for an acquisition-access period (AAP) that ranged from 0 to 72 h, followed by a 48 h inoculation-access period (IAP). Individual adult whiteflies were monitored for CdTV ingestion using polymerase chain reaction (PCR) to detect the viral coat protein gene (AV1 ORF), and transmission efficiency (frequency) was determined by allowing potentially viruliferous whiteflies access to tomato seedlings following each experimental AAP. PCR results for individual adult whiteflies indicated that CdTV was ingested from infected tomato plants by both biotypes 93% of the time. Transmission frequencies by both vector biotypes increased with longer AAPs. However, the AZ A biotype transmitted CdTV 50% of the time, compared to only 27% for the B biotype. Evidence that virus was ingested with equal competency by the A and B biotypes confirmed that both vectors were capable of ingesting CdTV from tomato at the same frequency, even when the AAP was 0.5 h. Consequently, either the acquisition and/or transmission stages of the pathway, rather than ingestion competency, were responsible for differences in vector-mediated transmissibility. Detection frequency of CdTV, after 48 h AAP, by PCR in single females of AZ B biotype was significantly higher than males.